In this section, we will go over how to define and use functions in the Scala programming language.

If you recall from the Scala Introduction tutorial, Scala is both an Object Oriented and Functional programming language. If you are new to functional programming - don't worry :) this chapter will help you learn about the various ways you can define and use functions in Scala.

Throughout the tutorials we will use the popular IntelliJ IDEA which we've setup in Chapter 1. I hope that by now you are more comfortable using IntelliJ. If not, feel free to review the previous tutorials from Chapter 1!

In this chapter, we will provide tutorials on the topics below. If none of these make any sense right now, that's OK :)

• Function introduction
• Function with an Option parameter
• Function with implicit parameters
• Function which itself is implicit
• Function which specifies type parameters
• Function which accepts variable arguments
• Function which can be defined as operators
• Function which accepts parameter groups
• Function which takes another function as parameter - Higher Order Functions
• Function which accepts a callback function as its parameter
• Function which are defined as values
• Function which can be composed together
• Function which is tail recursive
• Function which can be partial
• Function which can be nested within another function

So let's get started!